1. Field of the Invention
The present invention relates to an area control system for an image processing apparatus comprising an input unit for inputting image signals, an area control unit for generating control signals for each specified area according to its document type and processing mode, and a processing unit having a plurality of processing blocks for processing image signals by setting parameters in the respective processing blocks.
2. Description of the Prior Art
A digital copying machine is made up of an IIT (image input terminal) for reading an image on an original document, an IPS (image processing system) for processing image data, and an IOT (image output terminal) for driving a laser printer, for example, by image data to output a hard copy. In the IIT, a CCD sensor picks up image information on the original in the form of analog image signals which depend on reflectivities. Then, the analog image data signals are converted into multitone digital image data. In the IPS, the image data signals obtained by the IIT are processed for various types of corrections, conversion, edit and the like. In the IOT, according to the image data processed by the IPS, a laser device in the laser printer is turned on and off to depict and output a mesh-dot picture.
Thus, the digital copying machine can produce, by processing the multi-tone image data by the IPS according to the type of the image data, a sharp image edge-emphasized for characters, a smoothed image for a halftone image, such as photograph, and a color-adjusted color image of high reproduction performance. Further, the machine can makes various types of edit of the document image, such as painting for the original, color change, trimming, shift, composition, reduction, and enlargement. In a color digital copying machine, the IIT reads the document image after it is separated into three primary colors R (red), G (green), and B (blue), and supplies the image data of three colors to the IPS. In the IOT, mesh-dot images of toner colors Y (yellow), M (magenta), C (cyan), and K (black) are formed and superposedly composed. Accordingly, in the image processing system, such as a color digital copying machine, toner developing units are provided for the respective colors. A full-color image on an original document is read by successively scanning the document image four times in connection with the developing processes of the respective colors. The full-color image data thus read is processed.
The outline of the color digital copying machine thus constructed will be described with reference to Unexamined Japanese Patent Publication Hei-2-223275. FIG. 6 is a block diagram showing the arrangement of the conventional color digital copying machine.
In FIG. 6, an IIT 100 separates a color document image into three primary colors B, G, and R, and reads the images of the three colors by using a CCD sensor so that the images are converted into digital image signals. An IOT 115 reproduces a color image through the exposure process by the laser beam and the development processes. The components ranging from an END converter 101 to an IOT interface 110, which are located between the IIT 100 and the IOT 115, make up an image data edit processing system (image processing system (IPS)). In the IPS, color image data of B, G, and R are converted into image data of toner colors Y, M, and C, and further K (Black). Every developing cycle the toner color signal of the developing color is transferred to the IOT 115.
In the IIT 100, the CCD sensor reads the document images of B, G and R with the size of 16 dots/mm for each pixel, and outputs the read image data of 24 bits (3 colors.times.8 bits; 256 tones). The CCD sensor of 300 mm long and 16 dots/mm in density and having B, G and R filters attached to the upper surface thereof, performs a scan of 16 lines/mm at the process speed of 190.5 mm/sec. The sensor produces the image data at the speed of approximately 15 M pixels per second for each color. The IIT 100 logarithmic-converts the analog data of B, G and R pixels, whereby transforming the reflectivity information into the density information, and converting it into digital data.
The IPS receives the color separated signals B, G and R from the IIT 100, and processes the received image data in various ways for improving the reproduction performances of color, tone, definition, and the like. The IPS converts the coloring material signals of the developing process colors into on/off signals, and transfers the converted ones to the IOT. The END (equivalent neutral density) module 101 adjusts (converts) the color image signals to gray-balanced color image signals. A color masking module 102 converts the B, G and R signals into signals corresponding to the quantities of Y, M and C coloring materials, through a matrix operation. A document-size detecting module 103 detects the document size in a prescan mode, and erases (makes a frame-erasure) the platen color in a read scan mode. A color change module 104 makes the change for a specified color in a specific area according to an area signal supplied from the area image control module. A UCR (under-color removal) & black generation module 105 generates a proper quantity of black K so as not to lose the color purity, subtracts the equal quantities of the toner colors Y, M and C therefrom according to the quantity of black K, and gates the signals after removal of the under-colors of the K, and Y, M and C colors are removed according to the signals in a mono-color mode and a 4-full-color mode. A spatial filter 106 is a nonlinear digital filter having the function to restore the image from being blurred, and the function to remove moire from the image. A TRC (tone reproduction control) module 107 makes the adjustments of density, contrast, and color balance, and makes a negative/positive inversion and other processings for reproduction improvements. A enlargement/reduction module 108 is provided for enlarging and reducing the size of an image in the horizontal scan direction. Incidentally, the size adjustment in the vertical scan direction is performed by adjusting the speed of scanning the original. A screen generator 109 converts the toner color signals expressed in multi-tone into on/off or binary-coded signals according to the tones. The binary-coded toner color signals are output to the IOT 115, through an IOT interface module 110. An area image control module 111 includes an area generating circuit and a switch matrix. An edit control module includes an area command memory 112, a color palette video switch circuit 113, a font buffer 114, and the like, and performs various types of edits.
The area-image control module 111 is arranged so as to set seven rectangular areas and the priority order of them in an area generating circuit. In connection with the respective areas, control data for the areas are set in a switch matrix. The control data includes, for example, the data of color change, color-mode of mono-color or full-color, and modulation select for photograph, character or the like, and select data for TRC and screen generator, and is used for controlling the color masking module 102, color change module 104, UCR module 105, spatial filter 106, and TRC module 107. The switch matrix may be set by a software.
With the edit control module, the painting processing may be performed in a manner that it reads a document image, such as a circle graph, not a rectangular, and paints out, with a specified color, a specified area indefinite in area. 4-bit area commands are stored in a plane memory consisting of four planes. An edit command at each point on the document is set with 4 bits of the 4-plane memory.
Other image processing systems of the type in which an area is specified and edited in an image have been proposed in, for example, Unexamined Japanese Patent Publications Sho-62-181570, Sho-64-1369, and Sho-64-84977.
In the conventional color copying machine, when it performs the area edit and area processing, a control signal is generated for each area in each of various types of modes, such as the document type and the color mode, and applied to each processing block, such as the color masking module 102 and the color change module 104. The control signals used in the area-image control module 111 are, for example, MONO (mono-color), FULL (full color), SHARP.sub.0, SHARP.sub.1, ZERO, TRCSel.sub.0, TRCSel.sub.1, TRCSel.sub.2, SCRNUL and NENEDF. Under the circumstances, in such a case that the processing system or the processing block is changed and the number of control signals is increased, the area-image control module 111 as a control signal source is complicated in construction.